Electrical device



Sept. 25, 19 45. C.'T. BAXTER ELECTRICAL DEVICE Filed Jan. 2, 1943 g- 3Clemenr T Baxter IN E Passed Sept. as, 1945 UNITED STATES PATENT OFFICEELECTRICAL DEVICE Clement '1. Baxter, BeverlyhllaI alsignor to.

Sylvania Electric Products Inc Salem, Mace. a corporation ofMassachusetts Application Jannary z, 194:, Serial No. 411,202

1 Claim.

This invention relates to electrical devices and connections thereof. I

An object of this invention is to provide improved assembly ofelectrical devices and method of producing same.

Another object is to provide improved means and method of connectingwires in electrical devices.

Another object is to provide improved base assemblies in electricaldevices such as tubes and lamps, for example, luminescent or fluorescentlamps.

Another object is to provide improved base assemblies in electricaldevices such as tubes or lamps in which the wire connections are formedby clamping or crimping means rather than soldering, welding or thelike.

Other and further objects .will be apparent from the followingspecification and claim taken in conjunction with the drawing in which:

Figure 1 is an elevation in'partial section of an illustrativeembodiment of this invention;

Figure 2 is an enlargement of a contact pin or the structure of Figure1, with a pin illustrated in its pre-assembly contour; and

Figure 3 is an enlarged, isometric view, in

7 partial section of a base of the structure oi Figure 1.

Similar reference characters refer to similar parts in the several viewsof the drawing and in the following specification.

In electrical connections involving the connection of a wire to acontact or other member, it is customary and helpful to assemble acontact button or pin on the end of the wire to form rigid and uniformcontact ends for the wire. In radio tubes or light bulbs and similardevices this is accomplished by mounting a contact button or pin in thebase of the tube or lamps and securing a lead wire from inside the tube,to the button or pin.

This securing action ordinarily is done by soldering or welding.

This invention provides improved means and method of so securing wires,and in particular, provides an improved lamp base assembly.

As an illustration of an embodiment of this invention, the disclosuresof the drawing are directed to the formation of an electric gaseousdischarge lamp with particular reference to its end and base assemblies.

As in Figure 1, this illustration comprises mainly a glass lamp envelopeI having bases 2, and hollow contact pins 3 mounted in the bases 2.

A glass end portion 4 is sealed to the envelope (Cl.176-128) v l, andhas mounted therein a filament 5 not completely shown, and filamentleads 3 secured to the filament 3 in the glass end portion 4 and also tothe contact pins 3, mounted in the base 2. The base 2 is secured to theenvelope I and the glass end! by Bakelite cement I, or other suitablebinding means.

The glass end 4 is so formed as to extend into the envelope in a hollowelongation and the filament 5 is mounted therein substantially at theinner extremity of the elongation. A hollow tongue of glass 3, withinthe elongation, extends back toward the base 2, thereby forming aseparator for the two filament leads 6 which lie within the hollowcylinder of the glass end 4.

As in Figure 2, the lead wires 6 extend within the hollow contact pins 3and are clamped therein by annular, inner heads 9 of the pins 3.

The base 2, Figures '1 and 3, is preferably formed of a plastic,Bakelite, for example. The base is cup-shaped, with a base wall l0 andcylindrical side wall H. The base wall It) is provided with a pair ofopenings [2 in each of the contact pins 3 is located.

Each of the openings i2 has an inner countersunk portion 13 and an outercountersunk portion 14. The countersink l3 receives the fingers i5, seeFigure 2, of the contact pin 3, when they are rolled or bent outwardlyto aid in securing the pin 3 to the base 2.

Figure 2 illustrates the contour of the pin 3 prior to its assembly withthe base ID. The fingers I5 are bent inward so that the pin may bepushed through the opening i2v as an assembly step. The lead wire 6 isnot normally positioned within the pin 3 while the fingers l5 are turnedinward. It is so shown merely as an illustration of how the lead wire 6is assembled within the pin 3 and clamped therein by the inner lead 9.

The outer bead iii of the pin 3 is positioned and formed to overlie theouter countersink M of the base opening I! as shown in assembly inFigure l. The bead It has an important function in that in the assemblyas in Figure 1, it prevents pin 3 from being pushed through the openingl2 by pressure, for example such as may be applied to the pin 3 in theassembly or disassembly of the lamp with its socket. If desired, a verytight assembly of the pin 3 to the base 2 may be made by positioning theouter bead 16 within the countersink l4 so that rolling or bending thefingers l5 will pull the bead [6 against the bottom of the countersinkM. This in addition to having a close, binding fit between the pin 3 andthe opening l2, provides a tight assembly.

The bead It may be located completely outside, or partially orcompletely within the countersink Il. when it is completely within, theassembly has the advantage that the means of holding the pin 3 in theopening I2 is substantially hidden, and the overall thickness of thebase assembly v may be less.

socket. Further, the bead may be used as a lo- I cator or grip portionover which a forming or holding tool may be placed. The only requirementin this instance is that there be tool clearance about the bead IS. Thecountersink I4 is dimensioned with such a clearance.

Formation in the pin 3 of the inner bead 3 provides an outer annularrecess II which may be useful, in combination with the outer bead It, orby itself, as a locating or holding device, in connection with thesprings of a lamp socket.

The pin 3 as shown in Figure 2 is in its preassembly formation, with thehead 3 formed and in fairly close fitting relation with the lead wire 6andready for the final crimping to strongly bind the pin 3 to the wire8. If desired. however, the pin 3 may be assembled without the head 9 orthe annular recess I1 and crimped into binding relation with the wire 8from a cylindrical formation. This crimping may be at one or more pointsabout the periphery of the pin 3, or it may take the recess and beadform as in the prethe length of the lamps beyond the extent of the 45glass envelope I. An annular recess I8 is provided inside the base 2 toreceive the annular peripheral end 20 of the envelope I in its joinderwith the glass end portion 4. A central recess 2I is provided to affordclearance for the separator tongue 8. The necessary thickness for theaccommodation of the pins 3 is provided by the raised portion 22 whichtakes advantage of the inwardly extending tapered contour of the base ofthe glass'end l.

The side wall II extends over the annular end 20 of the envelope I. Theenvelope I is tapered to a reduced diameter at its ends so that theouter surface of the base wall II may be substantially flush with theouter surface of the envelope I. An annular groove as at 22 is formed inthe envelope I and this is. filled with the binder I as an aid tosecuring the base 2 to the envelope I.

The plastic base 2 has the advantage that the pins 3 are effectivelyinsulated from each other without the necessity of using insulationsleeves or the like in the mounting of the pins 3 to the base 2.

The assembly of the device as shown in the drawing is as follows:

The glass end portion 4 with the filament 5 and filament leads 3 mountedthereon, is fused or otherwise Joined with the glass envelope I. As asubassembly the pins 3, as shown in Figure 2 without the wire I, aremounted in the openings I2 of the base wall It and the fingers II turnedor bent over to flare outwardly and lie in the countersinks I3.

Bakelite cement I is placed in grooves 22 and I3 and the base 3 andenvelope I are assembled. Heat to the order of 200 degrees centigrade isapplied to the base 2 about its periphery to instigate the grippingaction of the cement I on the envelope I and base 2.

If the device used is a fluorescent lamp, the envelope I would have acoating of fluorescent material as in the usual construction of suchlamps.

What I claim is:

An end cap assembly for a substantially cylindrical gaseous dischargelamp envelope comprising a frangible reentrant stem portion sealed uponthe end of said envelope, lead wires extending through and sealed insaid stem portion, a unitary cup-shaped end cap of insulating materialadapted to be secured upon the end of said envelope the peripheralportion of the, bottom wall thereof being relatively thin and itscentral portion being relatively thick, a plurality of apertures in thethick portion of the bottom wall of the cup adapted to extendlongitudinally of the lamp-envelope and being counterbored at both ends,a plurality of contact members received in and extending outwardly fromsaid apertures having the form of a hollow cylinder and within whichsaid lead wires are received, an annular integral shoulder on saidcontact members upset outwardly therefrom and received in the outercounterbore of said apertures, the inner ends of said contact membersbeing expanded into the innercounterbore of the apertures therebyrigidly anchoring the pins in the end cap, and a narrow section of theoutwardly extending portion of said contact members being inwardlyswaged into contact with said lead wires to form a continuous annulardepressed bead.

CLEMENT T. BAXTER.

